no, it is possible for women to reproduce asexually but it would just need some extra help, by putting the necessary genetic code into the egg you could make a baby, the sperm cell is just a way of carrying that

Being lesbian doesn't stop them from being able to reproduce.
They just may not enjoy it. But how, when faced with the survival of the species, does enjoyment factor in?
There would be a law that every women has to have a child, and if they cannot find a suitable mate, they will be raped.

well what could happen is that he could reverse the statistics of straight and homosexual women thus leaving a sizable demographic of the population still being straight and thus allowing for the population to survive, if not for long